/**
 * 2010(c) Copyright Oceansoft Information System Co.,LTD. All rights reserved.
 * <p>
 * Compile: JDK 1.6+
 * <p>
 * 版权所有(C)：江苏欧索软件有限公司
 * <p>
 * 公司名称：江苏欧索软件有限公司
 * <p>
 * 公司地址：中国苏州科技城青山路1号
 * <p>
 * 网址: http://www.oceansoft.com.cn
 * <p>
 * 作者: 090922(陈伟)
 * <p>
 * 文件名: com.oceansoft.mobile.client.util.MD5Util.java
 * <p>
 * 类产生时间: 14-2-13 下午5:51
 * <p>
 * 负责人: 090922(陈伟)
 * <p>
 * Email:javacspring@gmail.com
 * <p>
 * 所在组 : 掌上公安应用平台
 * <p>
 * 所在部门: 开发部--手持技术部
 * <p>
 * <p>
 */
package cn.com.oceansoft.nos.common.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * MD5加密工具类
 *
 * @author: chenw
 * @time: 14-2-13 下午5:51
 */
public class MD5Util {

    /**
     * 默认的密码字符串组合，apache校验下载的文件的正确性用的就是默认的此组合
     */
    protected static char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
    protected static MessageDigest messagedigest = null;

    static {
        try {
            messagedigest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException nsaex) {
            System.err.println(MD5Util.class.getName() + "初始化失败，MessageDigest不支持MD5Util。");
            nsaex.printStackTrace();
        }
    }

    public static String MD5(String str) {
        //            MessageDigest message = MessageDigest.getInstance("MD5");
        messagedigest.update(str.getBytes());
        byte[] b = new byte[16];
        b = messagedigest.digest();
        String digestHexStr = "";
        for (int i = 0; i < 16; i++)
            digestHexStr += byteHEX(b[i]);
        return digestHexStr;
    }

    public static String byteHEX(byte ib) {
        char[] Digit = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        char[] ob = new char[2];
        ob[0] = Digit[(ib >>> 4) & 0X0F];
        ob[1] = Digit[ib & 0X0F];
        return new String(ob);
    }

    /**
     * 适用于上G大的文件
     *
     * @param file 待检验文件
     * @return MD5检验和
     * @throws IOException
     */
    public static String getFileMD5String(File file) throws IOException {
        FileInputStream in = new FileInputStream(file);
        FileChannel ch = in.getChannel();
        MappedByteBuffer byteBuffer = ch.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
        messagedigest.update(byteBuffer);
        return bufferToHex(messagedigest.digest());
    }

    public static String getMD5String(String s) {
        return getMD5String(s.getBytes());
    }

    public static String getMD5String(byte[] bytes) {
        messagedigest.update(bytes);
        return bufferToHex(messagedigest.digest());
    }

    private static String bufferToHex(byte bytes[]) {
        return bufferToHex(bytes, 0, bytes.length);
    }

    private static String bufferToHex(byte bytes[], int m, int n) {
        StringBuffer stringbuffer = new StringBuffer(2 * n);
        int k = m + n;
        for (int l = m; l < k; l++) {
            appendHexPair(bytes[l], stringbuffer);
        }
        return stringbuffer.toString();
    }

    private static void appendHexPair(byte bt, StringBuffer stringbuffer) {
        char c0 = hexDigits[(bt & 0xf0) >> 4];
        char c1 = hexDigits[bt & 0xf];
        stringbuffer.append(c0);
        stringbuffer.append(c1);
    }

    public static String md5(String str) {
        MessageDigest md5 = null;
        try {
            md5 = MessageDigest.getInstance("MD5");
            StringBuffer buf = new StringBuffer();
            md5.update(str.getBytes());
            byte bytes[] = md5.digest();
            int len = bytes.length;
            for (int i = 0; i < len; i++) {
                String s = Integer.toHexString(bytes[i] & 0xff);
                if (s.length() == 1) {
                    buf.append("0");
                }
                buf.append(s);
            }
            return buf.toString();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return "";
        }
    }

    // 可逆的加密算法
    public static String KL(String inStr) {
       // String s = new String(inStr);
       char[] a = inStr.toCharArray();
       for (int i = 0; i < a.length; i++) {
           a[i] = (char) (a[i] ^ 't');
           }
        String s = new String(a);
        return s;
        }
    // 加密后解密
            public static String JM(String inStr) {
        char[] a = inStr.toCharArray();
        for (int i = 0; i < a.length; i++) {
            a[i] = (char) (a[i] ^ 't');
            }
        String k = new String(a);
        return k;
        }
    public static void main(String[] args) {
       System.out.println( KL(String.valueOf(System.currentTimeMillis())));;
    }
}
